Mavis is a feisty ten-year-old who lives in rural Australia with her mum, dad and sister, Doreen.

It's World War Two, and Darwin is bombed. Life as she knows it changes.

Her dad and Uncle John dig a trench in the backyard, and school lessons are replaced with air raid drills. Mavis is keen to help the war effort at home, and an opportunity arises when a soldier comes to school seeking volunteers. Too young to help on her own, she convinces her older sister, Doreen, to join her in plane spotting.

Every Saturday, they climb the stairs of the town clock tower, armed with binoculars and pictures of bombers, to record the times and direction of aircraft. Planes come and go, but they are local friendlies. One Saturday, Mavis must work alone. She is nervous but determined to carry out her duty for the war effort at home. When an enemy plane comes into view, she is more excited than frightened! She rings it in and becomes a hero. That is until it's revealed the aircraft is a captured enemy plane that she just happened to see when the local air force was testing it.

Mavis feels deflated, but her spirits are boosted when Mum makes dessert in her honour and Dad lets her play in the trench. Mavis never sees another enemy plane, but after the war when she hears a rumble come over the hills of home, her eyes still search the skies.